On the basis of info you give us, I think there are several mistakes you made, so I must ask you some questions:
1. WHICH CC licence you were using? Because there are also CC licences that say: you can copy and spread my work, but you can't change it, nor use in commercial purposes. So, check the exact licence your site was having. This is the most important thing now.
Other than that, I really do not understand why did you give him your site — because if he wanted to "begin from the scratch", he could have easily create his own Wiki. At least creating a wiki here is easy.
2. When a former project head deleted the page in question, did he delete it completely or just re-nemed it to deleted: name-of-the-page? Because, if he had deleted it completely a new MA couldn't have possibly seen it, let alone restore it. So my guess is that he didn't and the new MA is a very mean man: he created a new page, then copy-pasted the contents of your "deleted page", and then deleted it forever. So, there's nothing you can do about it. The only hope is that your site was under http://www.example.com Attribution-Noncommercial-No Derivative Works 3.0 Unported. If this is a case, you can still tell him that this licence allows only the using, and copying of the contents, but not changing them in any way and that he is obliged by this licence to attribute the work to you. Read carefully the licence and you will see that it protects your work in a high level.
Other than that, if you had a free site, then the CC licence you have on it is only for the code, you are free to put any other licence to the contents, i.e. to all the text you put in your site. The code came from Wikidot, and it is fair that all new cod.s, themes, modules, etc, someone makes stays under the same CC licence Wikidot has. But the content is only yours and you have the right to do with it what you want, even to put All rights reserved. But this should have been written in a separate page and with the visible link at the home page. This is for you to know for the next time. You can still use Wikidot for your work, but first determine the correct licence and of course, do not give away your site to anyone!
But in any way, he did not have the right to tell you that what he told you. With GFDL/CC licences you give your work away to the world, yes, but this does not mean that you cease to be the author of the work. You are free to reuse it and do with it whatever you want. I'll give you a simple example. Everyone knows what is Wikipedia. So, when you write there something, you are giving it under GFDL licence. Therefore, you cannot retrieve your work, or decide which changes will be done. Everyone has the right to change it, or reuse it in some other article, or not… To use is whatever he is pleased. But this still does not mean that you are not an author of this work. You can take your text, and do whatever you want with it — publish it, put it in another web page, whatever… You just need to be sure that the text you are taking out form Wiki does not contain significant changes of other people. So, you have the right to take back that page you created, even though the history of this page does not contain your changes.
So, the first thing is to see WHAT CC licence you were using. When we know that, maybe we can tell you what you can do.